Preheat the oven to 350 degrees and grease a 9×5 loaf pan.

Then, make the brown butter. Add the diced butter to a small skillet or pot. Heat the skillet to medium heat. The butter will start to melt as the skillet heats up. Allow the butter to bubble and “cook” until it begins to change from a bright yellow color to a golden brown color. You will know the butter has “browned” when you see brown bits beginning to form in the bottom of the skillet. Remove the butter from the heat and transfer to a heat safe dish to cool while you make the banana bread.

Next, make the banana bread batter. In a large mixing bowl add the brown butter, mashed banana, spices, sugars, and vanilla extract. Stir until well combined. Next, add the sour cream and eggs and stir until well mixed.

Then, sift flour, baking soda, and salt into the banana bread batter. Mix until the flour is well incorporated, but be sure not to over mix.

Next, transfer about half of the batter to the loaf pan. Then, add your cinnamon-sugar mixture on top of the batter, but reserve about 2 tbsp for the top. Then, add the remaining batter. Smooth the top with the back of a spoon and then add the remaining 2 tbsp of the cinnamon sugar mixture. Use a knife to swirl the batter to create cinnamon-sugar swirls, but do not over swirl.

Next, slice one banana in half and press it into the top of the loaf, cut side up. Then, put the bread in the preheated oven and bake for 60-65 minutes or until a toothpick comes out clean with only a few small crumbs on the end.

Remove the bread from the oven and let the bread cool in the pan for 45 minutes before removing it from the pan and onto a wire rack to finish cooling completely. Once cool, slice, serve, and enjoy!